When a wheelchair scale is used for measuring the weight of a wheelchair user, a wheelchair in which the test subject is sitting is moved onto the scale and the total weight is measured first. Then, the weight of the test subject is determined by subtracting the weight of the wheelchair from the measured weight. If the weight of the wheelchair is known in advance, the weight of the test subject can be determined by inputting the weight of the wheelchair before the measurement and measuring the total weight of the wheelchair and the test subject.
Since the wheelchair scale measures the total weight including the weight of the wheelchair, which is about 100 kg if the wheelchair is an electrical wheelchair, it must have a maximum measurable weight of about 300 kg (about 660 lbs). In addition, since the wheelchair must be pushed manually or moved electrically onto a support base of the wheelchair scale, the height of the wheelchair scale must be as low as about 5 centimeters.
Accordingly, although the support base is generally reinforced by ribs which extend in X and Y directions or rectangular pipes which are joined together by welding, the size of a support base for supporting a wheelchair of about 40 to 75 centimeters or more is about 50 to 80 centimeters or more, and accurate weight measurement is difficult due to the deflection of the support base.
In addition, all of the members such as ribs and pipes must be assembled and successively welded one by one, which is cumbersome since there are a large number of portions to be welded.